Buggy code:
public void moveAbove ( Control control ) { } public void moveBelow ( Control control ) { } void overrideTranslations ( ) { } public void pack ( ) { } public void pack ( boolean changed ) { } void propagateChildren ( boolean enabled ) { } void propagateWidget ( boolean enabled ) { } void realizeChildren ( ) { } public void redraw ( ) { } public void redraw ( int x , int y , int width , int height , boolean all ) { } void redrawWidget ( int x , int y , int width , int height , boolean redrawAll , boolean allChildren ) { } void releaseChild ( ) { } void releaseWidget ( ) { } public void removeControlListener ( ControlListener listener ) { } public void removeFocusListener ( FocusListener listener ) { } public void removeHelpListener ( HelpListener listener ) { } public void removeKeyListener ( KeyListener listener ) { } public void removeMouseListener ( MouseListener listener ) { } public void removeMouseMoveListener ( MouseMoveListener listener ) { } public void removeMouseTrackListener ( MouseTrackListener listener ) { } public void removePaintListener ( PaintListener listener ) { } public void removeTraverseListener ( TraverseListener listener ) { } void sendHelpEvent ( int callData ) { } boolean sendMouseEvent ( int type ) { } boolean sendMouseEvent ( int type , int button , int count , int detail , boolean send , int time , int x , int y , int state ) { } boolean sendMouseEvent ( int type , XButtonEvent xEvent ) { } boolean sendMouseEvent ( int type , XCrossingEvent xEvent ) { } boolean sendMouseEvent ( int type , XMotionEvent xEvent ) { } public void setBackground ( Color color ) { } void setBackgroundPixel ( int pixel ) { } boolean setBounds ( int x , int y , int width , int height , boolean move , boolean resize ) { } public void setBounds ( int x , int y , int width , int height ) { } public void setBounds ( Rectangle rect ) { } public void setCapture ( boolean capture ) { } public void setCursor ( Cursor cursor ) { } public void setEnabled ( boolean enabled ) { } public boolean setFocus ( ) { } public void setFont ( Font font ) { } public void setForeground ( Color color ) { } void setForegroundPixel ( int pixel ) { } public void setLayoutData ( Object layoutData ) { } public void setLocation ( int x , int y ) { } public void setLocation ( Point location ) { } public void setMenu ( Menu menu ) { } public boolean setParent ( Composite parent ) { } void setParentTraversal ( ) { } boolean setRadioSelection ( boolean value ) { } public void setRedraw ( boolean redraw ) { } boolean setTabGroupFocus ( boolean next ) { } boolean setTabItemFocus ( boolean next ) { } public void setSize ( int width , int height ) { } public void setSize ( Point size ) { } public void setToolTipText ( String string ) { } public void setVisible ( boolean visible ) { } void setZOrder ( Control control , boolean above ) { } void setZOrder ( Control control , boolean above , boolean fixChildren ) { } void showMenu ( int x , int y ) { } public Point toControl ( int x , int y ) { } public Point toControl ( Point point ) { } public Point toDisplay ( int x , int y ) { } public Point toDisplay ( Point point ) { } boolean translateAccelerator ( char key , int keysym , XKeyEvent xEvent , boolean doit ) { } boolean translateMnemonic ( Event event , Control control ) { } boolean translateMnemonic ( char key , int keysym , XKeyEvent xEvent ) { } boolean translateTraversal ( int key , XKeyEvent xEvent ) { } int traversalCode ( int key , XKeyEvent xEvent ) { } boolean traverse ( Event event ) { } public boolean traverse ( int traversal ) { } boolean traverseEscape ( ) { } boolean traverseGroup ( boolean next ) { } boolean traverseItem ( boolean next ) { } boolean traversePage ( boolean next ) { } boolean traverseMnemonic ( char key ) { } boolean traverseReturn ( ) { } public void update ( ) { } void update ( boolean all ) { } void updateIM ( ) { } void updateLayout ( boolean all ) { } int XButtonPress ( int w , int client_data , int call_data , int continue_to_dispatch ) { } int XButtonRelease ( int w , int client_data , int call_data , int continue_to_dispatch ) { } int XEnterWindow ( int w , int client_data , int call_data , int continue_to_dispatch ) { XCrossingEvent xEvent = new XCrossingEvent ( ) ; OS . memmove ( xEvent , call_data , sizeof ) ; <START_BUG> if ( ( xEvent . mode ) != ( OS . NotifyNormal ) ) <END_BUG> return 0 ; if ( ( xEvent . subwindow ) != 0 ) return 0 ; sendMouseEvent ( MouseEnter , xEvent ) ; return 0 ; } int XExposure ( int w , int client_data , int call_data , int continue_to_dispatch ) { } int XFocusChange ( int w , int client_data , int call_data , int continue_to_dispatch ) { } int xFocusIn ( XFocusChangeEvent xEvent ) { } int xFocusOut ( XFocusChangeEvent xEvent ) { } int XKeyRelease ( int w , int client_data , int call_data , int continue_to_dispatch ) { } int XLeaveWindow ( int w , int client_data , int call_data , int continue_to_dispatch ) { } int XmNhelpCallback ( int w , int client_data , int call_data ) { } int XPointerMotion ( int w , int client_data , int call_data , int continue_to_dispatch ) { } }

Fix:
if ( ( ( xEvent . mode ) != ( OS . NotifyNormal ) ) && ( ( xEvent . mode ) != ( OS . NotifyUngrab ) ) )